Process for the catalytic disproportionation of methylnaphthalenes

ABSTRACT

A methylnaphthalene such as 2-methylnaphthalene undergoes catalytic disproportionation to naphthalene and a mixture of dimethylnaphthalene isomers, preferably containing substantial quantities of 2,6-dimethylnaphthalene, employing catalyst comprising zeolite characterized by an X-ray diffraction pattern including interplanar d-spacings at 12.36±0.4, 11.03±0.2, 8.83±0.14, 6.18±0.12, 6.00±0.10, 4.06±0.07, 3.91±0.07 and 3.42±0.06 Angstroms.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 254,524, filed Oct. 6, 1988, and a continuation-in-part of U.S.patent application Ser. No. 98,176, filed Sept. 18, 1987, now abandoned,which is a continuation-in-part of U.S. patent application Ser. No.890,268, filed July 29, 1986 . now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a process for the catalytic disproportionationof methylnaphthalenes to a mixture of naphthalene anddimethylnaphthalene isomers employing a synthetic porous crystallinematerial, or zeolite, as disproportionation catalyst.

Zeolitic materials, both natural and synthetic, have been demonstratedin the past to have catalytic properties for various types ofhydrocarbon conversion. Certain zeolitic materials are ordered, porouscrystalline aluminosilicates having a definite crystalline structure asdetermined by X-ray diffraction, within which there are a large numberof smaller cavities which may be interconnected by a number of stillsmaller channels or pores. These cavities and pores are uniform in sizewithin a specific zeolitic material. Since the dimensions of these poresare such as to accept for adsorption molecules of certain dimensionswhile rejecting those of larger dimensions, these materials have come tobe known as "molecular sieves" and are utilized in a variety of ways totake advantage of these properties. Such molecular sieves, both naturaland synthetic, include a wide variety of positive ion-containingcrystalline silicates. These silicates can be described as a rigidthree-dimensional framework of SiO₄ and Periodic Table Group IIIAelement oxide, e.g., A10₄, in which the tetrahedra are cross-linked bythe sharing of oxygen atoms whereby the ratio of the total Group IIIAelement, e.g., aluminum, and silicon atoms to oxygen atoms is 1:2. Theelectrovalence of the tetrahedra containing the Group IIIA element,e.g., aluminum, is balanced by the inclusion in the crystal of a cation,e.g., an alkali metal or an alkaline earth metal cation. This can beexpressed wherein the ratio of the Group IIA element, e.g., aluminum, tothe number of various cations, such as Ca/2, Sr/2, Na, K or Li, is equalto unity. One type of cation may be exchanged either entirely orpartially with another type of cation utilizing ion exchange techniquesin a conventional manner. By means of such cation exchange, it has beenpossible to vary the properties of a given silicate by suitableselection of the cation. The spaces between the tetrahedra are occupiedby molecules of water prior to dehydration.

Prior art techniques have resulted in the formation of a great varietyof synthetic zeolites. Many of these zeolites have come to be designatedby letter or other convenient symbols, as illustrated by zeolite Z (U.S.Pat. No. 2,882,243); zeolite X (U.S. Pat. No. 2,882,244); zeolite Y(U.S. Pat. No. 3,130,007); zeolite ZK-5 (U.S. Pat. No. 3,247,195);zeolite ZK-4 (U.S. Pat. No. 3,314,752); zeolite ZSM-5 (U.S. Pat. No.3,702,886); zeolite ZSM-11 (U.S. Pat. No. 3,709,979); zeolite ZSM-12(U.S. Pat. No. 3,832,449); zeolite ZSM-20 (U.S. Pat. No. 3,972,983);zeolite ZSM-35 (U.S. Pat. No. 4,016,245); and zeolite ZSM-23 (U.S. Pat.No. 4,076,842), merely to name a few.

The SiO₂ /Al₂ O₃ ratio of a given zeolite is often variable. Forexample, zeolite X can be synthesized with SiO₂ /Al₂ O₃ ratios of from 2to 3; zeolite Y, from 3 to about 6. In some zeolites, the upper limit ofthe SiO₂ /Al₂ O₃ ratio is unbounded. ZSM-5 is one such example whereinthe SiO₂ /Al₂ O₃ ratio is at least 5 and up to the limits of presentanalytical measurement techniques. U.S. Pat. No. 3,941,871 (Re. 29,948)discloses a porous crystalline silicate made from a reaction mixturecontaining no deliberately added alumina in the recipe and exhibitingthe X-ray diffraction pattern characteristic of ZSM-5. U.S. Pat. Nos.4,061,724, 4,073,865 and 4,104,294 describe crystalline silicates ofvarying alumina and metal content.

U.S. Pat. Nos. 3,855,328 and 4,418,235 both disclose thedisproportionation of methylnaphthalene over a zeolite catalyst toprovide a mixture of naphthalene and dimethylnaphthalenes. In the caseof U.S. Pat. No. 4,418,235, the zeolite is one having a silica toalumina ratio of at least 12 and a Constraint Index of about 1 to 12,e.g., ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35 and/or ZSM-38.

Japanese Patent No. J60092227-A appears to describe much the samedisproportionation process as U.S. Pat. No. 4,418,235, supra.

Japanese Patent No. J60045536-A appears to disclose the catalyzedtransmethylation of methylnaphthalenes to provide dimethylnaphthalenesemploying a zeolite catalyst having a silica to alumina ratio of 10-100and the distance between X-ray lattice faces specified therein.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a process for the catalyticdisproportionation of methylnaphthalenes to provide a mixture ofnaphthalene and dimethylnaphthalenes.

It is a particular object of the present invention to effect thecatalytic disproportionation of a feedstock containing at least onemethylnaphthalene with high selectivity for the 2,6-dimethylnaphthaleneisomer and relatively little of the more highly substituted, e.g., tri-and tetra-, methylnaphthalenes.

By way of realizing the foregoing and other objects of the invention, aprocess for the disproportionation of a methylnaphthalene is providedwhich comprises contacting at least one methylnaphthalene underdisproportionation reaction conditions with a disproportionationcatalyst to provide a product containing naphthalene and at least onedimethylnaphthalene, said disproportionation catalyst comprising asynthetic porous crystalline material characterized by an X-raydiffraction pattern including interplanar d-spacings at 12.36±0.4,11.03±0.2, 8.83±0.14, 6.18±0.12, 6.00±0.10, 4.06±0.07, 3.91±0.07 and3.42±0.06 Angstroms.

While the catalytic disproportionation process of this invention canprovide all 10 isomers of dimethylnaphthalene, it is relativelyselective for the production of 2,6-dimethylnaphthalene which is theprecursor of 2,6-naphthalenedicarboxylic acid, a valuable monomer forthe production of polyester. Most importantly, the process affords theproduction of dimethylnaphthalenes without significant production of themore highly substituted and commercially less valuablemethylnaphthalenes such as trimethylnaphthalenes andtetramethylnaphthalenes.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The entire contents of applications Ser. Nos. 254,524; 98,176; and890,268 are incorporated herein by reference.

Of the methylnaphthalenes which can undergo catalytic disproportionationin accordance with the present invention, 2-methylnaphthalene ispreferred. Where mixtures of methylnaphthalenes are employed, it ispreferred that they contain substantial quantities of2-methylnaphthalene, e.g., in amount of at least about 20 weightpercent, and preferably at least about 50 weight percent, of the totalweight of methylnaphthalenes present in the feed. In its calcined form,the synthetic porous crystalline material component employed in thecatalyst composition used in the process of this invention ischaracterized by an X-ray diffraction pattern including the followinglines:

                  TABLE A                                                         ______________________________________                                        Interplanar d-Spacing (A)                                                                    Relative Intensity, I/I.sub.o × 100                      ______________________________________                                        12.36 ± 0.4 M-VS                                                           11.03 ± 0.2 M-S                                                            8.83 ± 0.14 M-VS                                                           6.18 ± 0.12 M-VS                                                           6.00 ± 0.10 W-M                                                            4.06 ± 0.07 W-S                                                            3.91 ± 0.07 M-VS                                                           3.42 ± 0.06 VS                                                             ______________________________________                                    

Alternatively, it may be characterized by an X-ray diffraction patternin its calcined form including the following lines:

                  TABLE B                                                         ______________________________________                                        Interplanar d-Spacing (A)                                                                    Relative Intensity, I/I.sub.o × 100                      ______________________________________                                        30.0 ± 2.2  W-M                                                            22.1 ± 1.3  W                                                              12.36 ± 0.4 M-VS                                                           11.03 ± 0.2 M-S                                                            8.83 ± 0.14 M-VS                                                           6.18 ± 0.12 M-VS                                                           6.00 ± 0.10 W-M                                                            4.06 ± 0.07 W-S                                                            3.91 ± 0.07 M-VS                                                           3.42 ± 0.06 VS                                                             ______________________________________                                    

More specifically, the calcined form may be characterized by an X-raydiffraction pattern including the following lines:

                  TABLE C                                                         ______________________________________                                        Interplanar d-Spacing (A)                                                                    Relative Intensity, I/I.sub.o × 100                      ______________________________________                                        12.36 ± 0.4 M-VS                                                           11.03 ± 0.2 M-S                                                            8.83 ± 0.14 M-VS                                                           6.86 ± 0.14 W-M                                                            6.18 ± 0.12 M-VS                                                           6.00 ± 0.10 W-M                                                            5.54 ± 0.10 W-M                                                            4.92 ± 0.09 W                                                              4.64 ± 0.08 W                                                              4.41 ± 0.08 W-M                                                            4.25 ± 0.08 W                                                              4.10 ± 0.07 W-S                                                            4.06 ± 0.07 W-S                                                            3.91 ± 0.07 M-VS                                                           3.75 ± 0.06 W-M                                                            3.56 ± 0.06 W-M                                                            3.42 ± 0.06 VS                                                             3.30 ± 0.05 W-M                                                            3.20 ± 0.05 W-M                                                            3.14 ± 0.05 W-M                                                            3.07 ± 0.05 W                                                              2.99 ± 0.05 W                                                              2.82 ± 0.05 W                                                              2.78 ± 0.05 W                                                              2.68 ± 0.05 W                                                              2.59 ± 0.05 W                                                              ______________________________________                                    

Most specifically, it may be characterized in its calcined form by anX-ray diffraction pattern including the following lines:

                  TABLE D                                                         ______________________________________                                        Interplanar d-Spacing (A)                                                                    Relative Intensity, I/I.sub.o × 100                      ______________________________________                                        30.0 ± 2.2  W-M                                                            22.1 ± 1.3  W                                                              12.36 ± 0.4 M-VS                                                           11.03 ± 0.2 M-S                                                            8.83 ± 0.14 M-VS                                                           6.86 ± 0.14 W-M                                                            6.18 ± 0.12 M-VS                                                           6.00 ± 0.10 W-M                                                            5.54 ± 0.10 W-M                                                            4.92 ± 0.09 W                                                              4.64 ± 0.08 W                                                              4.41 ± 0.08 W-M                                                            4.25 ± 0.08 W                                                              4.10 ± 0.07 W-S                                                            4.06 ± 0.07 W-S                                                            3.91 ± 0.07 M-VS                                                           3.75 ± 0.06 W-M                                                            3.56 ± 0.06 W-M                                                            3.42 ± 0.06 VS                                                             3.30 ± 0.05 W-M                                                            3.20 ± 0.05 W-M                                                            3.14 ± 0.05 W-M                                                            3.07 ± 0.05 W                                                              2.99 ± 0.05 W                                                              2.82 ± 0.05 W                                                              2.78 ± 0.05 W                                                              2.68 ± 0.05 W                                                              2.59 ± 0.05 W                                                              ______________________________________                                    

These values were determined by standard techniques. The radiation wasthe K-alpha doublet of copper and a diffractometer equipped with ascintillation counter and an associated computer was used. The peakheights, I, and the positions as a function of 2 theta, where theta isthe Bragg angle, were determined using algorithms on the computerassociated with the diffractometer. From these, the relativeintensities, 100 I/I_(o), where I_(o) is the intensity of the strongestline or peak, and d (obs.) the interplanar spacing in Angstrom Units(A), corresponding to the recorded lines, were determined. In TablesA-D, the relative intensities are given in terms of the symbols W=weak,M=medium, S=strong, VS=very strong. In terms of intensities, these maybe generally designated as follows:

W=0-20

M=20-40

S=40-60

VS=60-100

It should be understood that these X-ray diffraction patterns arecharacteristic of all species of the zeolite. The sodium form as well asother cationic forms reveal substantially the same pattern with someminor shifts in interplanar spacing and variation in relative intensity.Other minor variations can occur depending on the ratio of structuralcomponents, e.g. silicon to aluminum mole ratio of the particularsample, as well as its degree of thermal treatment.

Examples of such porous crystalline materials include the PSH-3composition of U.S. Pat. No. 4,439,409, incorporated herein byreference, and MCM-22.

Zeolite MCM-22 has a composition involving the molar relationship:

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein X is a trivalent element, such as aluminum, boron, iron and/orgallium, preferably aluminum, Y is a tetravalent element such as siliconand/or germanium, preferably silicon, and n is at least about 10,usually from about 10 to about 150, more usually from about 10 to about60, and even more usually from about 20 to about 40. In theas-synthesized form, zeolite MCM-22 has a formula, on an anhydrous basisand in terms of moles of oxides per n moles of YO₂, as follows:

    (0.005-0.1)Na.sub.2 O:(1-4)R:X.sub.2 O.sub.3 :nYO.sub.2

wherein R is an organic component. The Na and R components areassociated with the zeolite as a result of their presence duringcrystallization, and are easily removed by post-crystallization methodshereinafter more particularly described.

Zeolite MCM-22 is thermally stable and exhibits a high surface areagreater than about 400 m² /gm as measured by the BET (Bruenauer, Emmetand Teller) test and unusually large sorption capacity when compared topreviously described crystal structures having similar X-ray diffractionpatterns. As is evident from the above formula, MCM-22 is synthesizednearly free of Na cations and thus possesses acid catalysis activity assynthesized. It can, therefore, be used as a component of the alkylationcatalyst composition herein without having to first undergo an exchangestep. To the extent desired, however, the original sodium cations of theas-synthesized material can be replaced in accordance with techniqueswell known in the art, at least in part, by ion exchange with othercations. Preferred replacement cations include metal ions, hydrogenions, hydrogen precursor, e.g., ammonium, ions and mixtures thereof.Particularly preferred cations are those which tailor the activity ofthe catalyst for methylnaphthalene disproportionation. These includehydrogen, rare earth metals and metals of Groups IIA, IIIA, IVA, IB,IIB, IIIB, IVB and VIII of the Periodic Table of the Elements.

In its calcined form, zeolite MCM-22 appears to be made up of a singlecrystal phase with little or no detectable impurity crystal phases andhas an X-ray diffraction pattern including the lines listed in aboveTables A-D.

Prior to its use as disproportionation catalyst, the zeolite crystalsshould be subjected to thermal treatment to remove part or all of anyorganic constituent present therein.

The zeolite disproportionation catalyst herein can also be used inintimate combination with a hydrogenating component such as tungsten,vanadium, molybdenum, rhenium, nickel, cobalt, chromium, manganese, or anoble metal such as platinum or palladium where ahydrogenation-dehydrogenation function is to be performed. Suchcomponent can be introduced in the catalyst composition by way ofco-crystallization, exchanged into the composition to the extent a GroupIIIA element, e.g., aluminum, is in the structure, impregnated thereinor intimately physically admixed therewith. Such component can beimpregnated in, or on, the zeolite such as, for example, by, in the caseof platinum, treating the zeolite with a solution containing a platinummetal-containing ion. Thus, suitable platinum compounds for this purposeinclude chloroplatinic acid, platinous chloride and various compoundscontaining a platinum amine complex.

The zeolite, especially in its metal, hydrogen and ammonium forms, canbe beneficially converted to another form by thermal treatment. Thisthermal treatment is generally performed by heating one of these formsat a temperature of at least about 370° C. for at least 1 minute andgenerally not longer than 20 hours. While subatmospheric pressure can beemployed for the thermal treatment, atmospheric pressure is preferredsimply for reasons of convenience. The thermal treatment can beperformed at a temperature of up to about 925° C.

Prior to its use in the disproportionation process of this invention,the zeolite crystals should be at least partially dehydrated. This canbe done by heating the crystals to a temperature in the range of fromabout 200° C. to about 595° C. in an atmosphere such as air, nitrogen,etc., and at atmospheric, subatmospheric or superatmospheric pressuresfor between about 30 minutes to about 48 hours. Dehydration can also beperformed at room temperature merely by placing the crystalline materialin a vacuum, but a longer time is required to obtain a sufficient amountof dehydration.

Zeolite MCM-22 can be prpared from a reaction mixture containing sourcesof alkali or alkaline earth metal (M), e.g., sodium or potassium,cation, an oxide of trivalent element X, e.g., aluminum, an oxide oftetravalent element Y, e.g., silicon, an organic (R) directing agent,hereinafter more particularly described, and water, said reactionmixture having a composition, in terms of mole ratios of oxides, withinthe following ranges:

    ______________________________________                                        Reactants      Useful       Preferred                                         ______________________________________                                        YO.sub.2 /X.sub.2 O.sub.3                                                                      10-60       10-40                                            H.sub.2 O/YO.sub.2                                                                             5-100       10-50                                            OH.sup.- /YO.sub.2                                                                           0.01-1.0     0.1-0.5                                           M/YO.sub.2     0.01-2.0     0.1-1.0                                           R/YO.sub.2     0.05-1.0     0.1-0.5                                           ______________________________________                                    

In a preferred method of synthesizing zeolite MCM-22, the YO₂ reactantcontains a substantial amount of solid YO₂, e.g., at least about 30 wt.% solid YO₂. Where YO₂ is silica, the use of a silica source containingat least about 30 wt. % solid silica, e.g., Ultrasil (a precipitated,spray dried silica containing about 90 wt. % silica) or HiSil (aprecipitated hydrated SiO₂ containing about 87 wt. % silica, about 6 wt.% free H₂ O and about 4.5 wt. % bound H₂ O of hydration and having aparticle size of about 0.02 micron) favors crystal formation from theabove mixture and is a distinct improvement over the synthesis methoddisclosed in U.S. Pat. No. 4,439,409. If another source of oxide ofsilicon, e.g., Q-Brand (a sodium silicate comprised of about 28.8 wt. %of SiO₂, 8.9 wt. % Na₂ O and 62.3 wt. % H₂ O) is used, crystallizationmay yield little if any MCM-22 crystalline material and impurity phasesof other crystal structures, e.g., ZSM-12, may be produced. Preferably,therefore, the YO₂, e.g., silica, source contains at least about 30 wt.% solid YO₂, e.g., silica, and more preferably at least about 40 wt. %solid YO₂, e.g., silica. Crystallization of the MCM-22 crystallinematerial can be carried out at either static or stirred conditions in asuitable reactor vessel such as, e.g., polypropylene jars orteflon-lined or stainless steel autoclaves. The total useful range oftemperatures for crystallization is from about 80° C. to about 225° C.for a time sufficient for crystallization to occur at the temperatureused, e.g., from about 25 hours to about 60 days. Thereafter, thecrystals are separated from the liquid and recovered.

The organic directing agent for use in synthesizing zeolite MCM-22 fromthe above reaction mixture is hexamethyleneimine.

It should be realized that the reaction mixture components can besupplied by more than one source. The reaction mixture can be preparedeither batchwise or continuously. Crystal size and crystallization timeof the MCM-22 crystalline material will vary with the nature of thereaction mixture employed and the crystallization conditions.

In all cases, synthesis of the MCM-22 crystals is facilitated by thepresence of at least about 0.01 percent, preferably about 0.10 percentand still more preferably about 1 percent, seed crystals based on thetotal weight of the crystalline product formed.

The zeolite crystals can be shaped into a wide variety of particlesizes. Generally speaking, the particles can be in the form of a powder,a granule, or a molded product such as an extrudate having a particlesize sufficient to pass through a 2 mesh (Tyler) screen and besubstantially retained on a 400 mesh (Tyler) screen. In cases where thecatalyst is molded, such as by extrusion, the crystals can be extrudedbefore drying or partially dried and then extruded.

It may be desired to incorporate the zeolite crystalline material withanother material which is resistant to the temperatures and otherconditions employed in the disproportionation process of this invention.Such materials include active and inactive materials and synthetic ornaturally occurring zeolites as well as inorganic materials such asclays, silica and/or metal oxides such as alumina. The latter may beeither naturally occurring or in the form of gelatinous precipitates orgels including mixtures of silica and metal oxides. Use of a material inconjunction with the zeolite, i.e., combined therewith or present duringits synthesis, which itself is catalytically active may change theconversion and/or selectivity of the catalyst. Inactive materialssuitably serve as diluents to control the amount of conversion so thatdimethylnaphthalene disproportionation products can be obtainedeconomically and orderly without employing other means for controllingthe rate of reaction. These materials may be incorporated into naturallyoccurring clays, e.g., bentonite and kaolin, to improve the crushstrength of the catalyst under commercial disproportionation operatingconditions. Said materials, i.e., clays, oxides, etc., function asbinders for the catalyst. It is desirable to provide a catalyst havinggood crush strength because in commercial use, it is desirable toprevent the catalyst from breaking down into powder-like materials.These clay binders have been employed normally only for the purpose ofimproving the crush strength of the catalyst.

Naturally occurring clays which can be composited with the zeolitecrystals include the montmorillonite and kaolin family, which familiesinclude the subbentonites, and the kaolins commonly known as Dixie,McNamee, Georgia and Florida clays or others in which the main mineralconstituent is halloysite, kaolinite, dickite, nacrite, or anauxite.Such clays can be used in the raw state as originally mined or initiallysubjected to calcination, acid treatment or chemical modification.Binders useful for compositing with the zeolite also include inorganicoxides, notably alumina.

In addition to the foregoing materials, the zeolite crystals can becomposited with a porous matrix material such as silica-alumina,silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania as well as ternary compositions such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia. It may also be advantageous to provide atleast a part of the foregoing matrix materials in colloidal form so asto facilitate extrusion of the bound catalyst component(s).

The relative proportions of finely divided crystalline material andinorganic oxide matrix vary widely, with the crystal content rangingfrom about 1 to about 95 percent by weight and more usually,particularly when the composite is prepared in the form of beads, in therange of about 2 to about 80 weight percent of the composite.

The stability of the zeolite catalyst may be increased by steaming, withsuitable steam stabilization conditions including contacting thecatalyst with, for example, 5-100% steam at a temperature of at least300° C. (e.g. 300°-650° C.) for at least one hour (e.g. 1-200 hours) ata pressure of 100-2,500 kPa. In a more particular embodiment, thecatalyst can be made to undergo steaming with 75-100% steam at 315°-500°C. and atmospheric pressure for 2-25 hours.

The methylnaphthalene disproportionation process of this invention isconducted such that the feedstock containing methylnaphthalene(s) isbrought into contact with the zeolite catalyst composition in a suitablereaction zone such as, for example, in a flow reactor containing a fixedbed of the catalyst composition, under effective disproportionationconditions. Such conditions include a temperature of from about 300° toabout 675° C., and preferably from about 375° to about 575° C., apressure of from about atmospheric to about 2000 psig and preferablyfrom about 20 to about 1000 psig and a feed weight hourly space velocity(WHSV) of from about 0.1 to about 500 hr⁻¹ and preferably from about 0.5to about 100 hr⁻¹. The WHSV is based upon the weight of the catalystcomposition employed, i.e., the total weight of active catalyst (andbinder if present). The feedstock can be in either the vapor phase orthe liquid phase and can be neat, i.e., free from intentional admixtureor dilution with other material, or it can be brought into contact withthe zeolite catalyst composition with the aid of carrier gases ordiluents such as, for example, hydrogen or nitrogen.

The disproportionation process described herein can be carried out as abatch-type, semi-continuous or continuous operation utilizing a fixed ormoving bed catalyst system. A preferred embodiment entails use of acatalyst zone wherein the methylnaphthalene charge is passedconcurrently or countercurrently through a moving bed of particle-formcatalyst. The latter, after use, is conducted to a regeneration zonewhere coke is burned from the catalyst in an oxygen-containingatmosphere (such as air) at elevated temperature, after which theregenerated catalyst is recycled to the conversion zone for furthercontact with the organic reactants.

In order to more fully illustrate the disproportionation process of thisinvention and the manner of practicing same, the following examples arepresented. In examples illustrative of the synthesis of zeolitecatalyst, whenever sorption data are set forth for comparison ofsorptive capacities for water, cyclohexane and/or n-hexane, they wereEquilibrium Adsorption values determined as follows:

A weighed sample of the calcined adsorbent was contacted with thedesired pure adsorbate vapor in an adsorption chamber, evacuated to lessthan 1 mm Hg and contacted with 12 Torr of water vapor or 40 Torr ofn-hexane or 40 Torr of cyclohexane vapor, pressures less than thevapor-liquid equilibrium pressure of the respective adsorbate at 90° C.The pressure was kept constant (within about ±0.5 mm Hg) by addition ofadsorbate vapor controlled by a manostat during the adsorption period,which did not exceed about 8 hours. As adsorbate was adsorbed by thecrystalline material, the decrease in pressure caused the manostat toopen a valve which admitted more adsorbate vapor to the chamber torestore the above control pressures. Sorption was complete when thepressure change was not sufficient to activate the manostat. Theincrease in weight was calculated as the adsorption capacity of thesample in g/100 g of calcined adsorbant. Zeolite MCM-22 always exhibitsEquilibrium Adsorption values of greater than about 10 wt. % for watervapor, greater than about 4.5 wt. %, usually greater than about 7 wt. %for cyclohexane vapor and greater than about 10 wt. % for n-hexanevapor. These vapor sorption capacities are a notable distinguishingfeature of zeolite MCM-22 and are preferred for the zeolite component ofthe catalyst for use herein.

When Alpha Value is examined, it is noted that the Alpha Value is anapproximate indication of the catalytic cracking activity of thecatalyst compared to a standard catalyst and it gives the relative rateconstant (rate of normal hexane conversion per volume of catalyst perunit time). It is based on the activity of the highly activesilica-alumina cracking catalyst taken as an Alpha of 1 (RateConstant=0.016 sec⁻¹). The Alpha Test is described in U.S. Pat. No.3,354,078, in the Journal of Catalysis, Vol. 4, p. 527 (1965); Vol. 6,p. 278 (1966); and Vol. 61, p. 395 (1980), each incorporated herein byreference as to that description. The experimental conditions of thetest used herein include a constant temperature of 538° C. and avariable flow rate as described in detail in the Journal of Catalysis,Vol. 61, p. 395.

EXAMPLE 1

One part of sodium aluminate (43.5% Al₂ O₃, 32.2% Na₂ O, 25.6% H₂ O) wasdissolved in a solution containing 1 part of 50% NaOH solution and103.13 parts H₂ O. To this was added 4.50 parts hexamethyleneimine. Theresulting solution was added to 8.55 parts of Ultrasil, a precipitated,spray-dried silica (about 90% SiO₂).

The reaction mixture had the following composition, in mole ratios:

SiO₂ /Al₂ O₃ =30.0

OH⁻ /SiO₂ =0.18

H₂ O/SiO₂ =44.9

Na/SiO₂ =0.18

R/SiO₂ =0.35

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor, withstirring, at 150° C. for 7 days. The crystalline product was filtered,washed with water and dried at 120° C. After a 20 hour calcination at538° C., the X-ray diffraction pattern contained the major lines listedin Table E. The sorption capacities of the calcined material weremeasured to be:

    ______________________________________                                        H.sub.2 O            15.2 wt. %                                               Cyclohexane          14.6 wt. %                                               n-Hexane             16.7 wt. %                                               ______________________________________                                    

The surface area of the calcined crystalline material was measured to be494 m² /g.

The chemical composition of the uncalcined material was determined to beas follows:

    ______________________________________                                               Component                                                                             wt. %                                                          ______________________________________                                               SiO.sub.2                                                                             66.9                                                                  Al.sub.2 O.sub.3                                                                      5.40                                                                  Na      0.03                                                                  N       2.27                                                                  Ash     76.3                                                           ______________________________________                                         SiO.sub.2 /Al.sub.2 O.sub.3, mole ratio = 21.1                           

                  TABLE E                                                         ______________________________________                                        Degrees        Interplanar                                                    2-Theta        d-Spacing (A)                                                                            I/I.sub.o                                           ______________________________________                                         2.80          31.55      25                                                   4.02          21.98      10                                                   7.10          12.45      96                                                   7.95          11.12      47                                                  10.00          8.85       51                                                  12.90          6.86       11                                                  14.34          6.18       42                                                  14.72          6.02       15                                                  15.90          5.57       20                                                  17.81          4.98        5                                                  20.20          4.40       20                                                  20.91          4.25        5                                                  21.59          4.12       20                                                  21.92          4.06       13                                                  22.67          3.92       30                                                  23.70          3.75       13                                                  24.97          3.57       15                                                  25.01          3.56       20                                                  26.00          3.43       100                                                 26.69          3.31       14                                                  27.75          3.21       15                                                  28.52          3.13       10                                                  29.01          3.08        5                                                  29.71          3.01        5                                                  31.61           2.830      5                                                  32.21           2.779      5                                                  33.35           2.687      5                                                  34.61           2.592      5                                                  ______________________________________                                    

EXAMPLE 2

A portion of the calcined crystalline product of Example 1 was tested inthe Alpha Test and was found to have an Alpha Value of 224.

EXAMPLES 3-5

Three separate synthesis reaction mixtures were prepared withcompositions indicated in Table F. The mixtures were prepared withsodium aluminate, sodium hydroxide, Ultrasil, hexamethyleneimine (R) andwater. The mixtures were maintained at 150° C., 143° C. and 150° C.,respectively, for 7, 8 and 6 days respectively in stainless steelautoclaves at autogenous pressure. Solids were separated from anyunreacted components by filtration and then water washed, followed bydrying at 120° C. The product crystals were analyzed by X-raydiffraction, sorption, surface area and chemical analyses. The resultsof the sorption, surface area and chemical analyses are presented inTable F. The sorption and surface area measurements were of the calcinedproduct.

                  TABLE F                                                         ______________________________________                                        Example          3         4       5                                          ______________________________________                                        Synthesis Mixture, mole ratios                                                SiO.sub.2 /Al.sub.2 O.sub.3                                                                    30.0      30.0    30.0                                       OH.sup.- /SiO.sub.2                                                                            0.18      0.18    0.18                                       H.sub.2 O/SiO.sub.2                                                                            19.4      19.4    44.9                                       Na/SiO.sub.2     0.18      0.18    0.18                                       R/SiO.sub.2      0.35      0.35    0.35                                       Product Composition, Wt. %                                                    SiO.sub.2        64.3      68.5    74.5                                       Al.sub.2 O.sub.3 4.85      5.58    4.87                                       Na               0.08      0.05    0.01                                       N                2.40      2.33    2.12                                       Ash              77.1      77.3    78.2                                       SiO.sub.2 /Al.sub.2 O.sub.3, mole ratio                                                        22.5      20.9    26.0                                       Adsorption, Wt. %                                                             H.sub.2 O        14.9      13.6    14.6                                       Cyclohexane      12.5      12.2    13.6                                       n-Hexane         14.6      16.2    19.0                                       Surface Area, m.sup.2 /g                                                                       481       492     487                                        ______________________________________                                    

EXAMPLE 6

Quantities of the calcined (538° C. for 3 hours) crystalline silicateproducts of Examples 3, 4 and 5 were tested in the Alpha Test and foundto have Alpha Values of 227, 180 and 187, respectively.

EXAMPLE 7

To demonstrate a further preparation of the present zeolite, 4.49 partsof hexamethyleneimine was added to a solution containing 1 part ofsodium aluminate, 1 part of 50% NaOH solution and 44.19 parts of H₂ O.To the combined solution were added 8.54 parts of Ultrasil silica. Themixture was crystallized with agitation at 145° C. for 59 hours and theresultant product was water washed and dried at 120° C.

Product chemical composition, surface area and adsorption analysesresults were as set forth in Table G:

                  TABLE G                                                         ______________________________________                                        Product Composition (uncalcined)                                              C                       12.1   wt. %                                          N                       1.98   wt. %                                          Na                      640    ppm                                            Al.sub.2 O.sub.3        5.0    wt. %                                          SiO.sub.2               74.9   wt. %                                          SiO.sub.2 /Al.sub.2 O.sub.3, mole ratio 25.4                                  Adsorption, wt. %                                                             Cyclohexane             9.1                                                   N-Hexane                14.9                                                  H.sub.2 O               16.8                                                  Surface Area, m.sup.2 /g                                                                              479                                                   ______________________________________                                    

EXAMPLE 8

Twenty-five grams of solid crystal product from Example 7 were calcinedin a flowing nitrogen atmospheres at 538° C. for 5 hours, followed bypurging with 5% oxygen gas (balance N₂) for another 16 hours at 538° C.

Individual 3 g samples of the calcined material were ion-exchanged with100 ml of 0.1N TEABr, TPABr and LaCl₃ solution separately. Each exchangewas carried out at ambient temperature for 24 hours and repeated threetimes. The exchanged samples were collected by filtration, water-washedto be halide-free and dried. The compositions of the exchanged samplesare tabulated below.

    ______________________________________                                        Exchange Ions                                                                 Ionic Composition, wt. %                                                                     TEA        TPA     La                                          ______________________________________                                        Na              0.095      0.089   0.063                                      N              0.30       0.38    0.03                                        C              2.89       3.63    --                                          La             --         --      1.04                                        ______________________________________                                    

EXAMPLE 9

The La-exchanged sample from Example 8 was sized to 14 to 25 mesh andthen calcined in air at 538° C. for 3 hours. The calcined material hadan Alpha Value of 173.

EXAMPLE 10

The calcined sample La-exchanged material from Example 9 was severelysteamed at 649° C. in 100% steam for 2 hours. The steamed sample had anAlpha Value of 22, demonstrating that the zeolite had very goodstability under severe hydrothermal treatment.

EXAMPLE 11

This example illustrates the preparation of the present zeolite where Xin the general formula, supra, is boron. Boric acid, 2.59 parts, wasadded to a solution containing 1 part of 45% KOH solution and 42.96parts H₂ O. To this was added 8.56 parts of Ultrasil silica, and themixture was thoroughly homogenized. A 3.88 parts quantity ofhexamethyleneimine was added to the mixture.

The reaction mixture had the following composition in mole ratios:

SiO₂ /B₂ O₃ =6.1

OH⁻ /SiO₂ =0.06

H₂ O/SiO₂ =19.0

K/SiO₂ =0.06

R/SiO₂ =0.30

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor, withagitation, at 150° C. for 8 days. The crystalline product was filtered,washed with water and dried at 120° C. A portion of the product wascalcined for 6 hours at 540° C. and found to have the following sorptioncapacities:

    ______________________________________                                        H.sub.2 O            11.7 wt. %                                               Cyclohexane           7.5 wt. %                                               n-Hexane             11.4 wt. %                                               ______________________________________                                    

The surface area of the calcined crystalline material was measured (BET)to be 405 m² /g.

The chemical composition of the uncalcined material was determined to beas follows:

    ______________________________________                                               N            1.94   wt. %                                                     Na           175    ppm                                                       K            0.60   wt. %                                                     Boron        1.04   wt. %                                                     Al.sub.2 O.sub.3                                                                           920    ppm                                                       SiO.sub.2    75.9   wt. %                                                     Ash          74.11  wt. %                                              ______________________________________                                         SiO.sub.2 /Al.sub.2 O.sub.3, molar ratio = 1406                               SiO.sub.2 /(Al + B).sub.2 O.sub.3, molar ratio = 25.8                    

EXAMPLE 12

A portion of the calcined crystalline product of Example 11 was treatedwith NH₄ Cl and again calcined. The final crystalline product was testedin the Alpha Test and found to have an Alpha Value of 1.

EXAMPLE 13

This example illustrates another preparation of the zeolite in which Xof the general formula, supra, is boron. Boric acid, 2.23 parts, wasadded to a solution of 1 part of 50% NaOH solution and 73.89 parts H₂ O.To this solution was added 15.29 parts of HiSil silica followed by 6.69parts of hexamethyleneimine. The reaction mixture had the followingcomposition in mole ratios:

SiO₂ /B₂ O₃ =12.3

OH⁻ /SiO₂ =0.056

H₂ O/SiO₂ =18.6

K/SiO₂ =0.056

R/SiO₂ =0.30

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor, withagitation, at 300° C. for 9 days. The crystalline product was filtered,washed with water and dried at 120° C. The sorption capacities of thecalcined material (6 hours at 540° C.) were measured:

    ______________________________________                                        H.sub.2 O            14.4 wt. %                                               Cyclohexane           4.6 wt. %                                               n-Hexane             14.0 wt. %                                               ______________________________________                                    

The surface area of the calcined crystalline material was measured to be438 m² /g.

The chemical composition of the uncalcined material was determined to beas follows:

    ______________________________________                                               Component                                                                             Wt. %                                                          ______________________________________                                               N       2.48                                                                  Na      0.06                                                                  Boron   0.83                                                                  Al.sub.2 O.sub.3                                                                      0.50                                                                  SiO.sub.2                                                                             73.4                                                           ______________________________________                                         SiO.sub.2 /Al.sub.2 O.sub.3, molar ratio = 249                                SiO.sub.2 /(Al + B).sub.2 O.sub.3, molar ratio = 28.2                    

EXAMPLE 14

A portion of the calcined crystalline product of Example 13 was testedin the Alpha Test and found to have an Alpha Value of 5.

EXAMPLE 15

This Example illustrates the use of zeolite MCM-22 in thedisproportionation of 2-methylnaphthalenes. The zeolite was prepared byadding adding 4.49 parts hexamethyleneimine to a mixture containing 1.00part sodium aluminate, 1.00 part 50% NaOH, 8.54 parts Ultrasil VN3 and44.19 parts deionized H₂ O. The reaction mixture was heated to 143° C.(290° F.) and stirred in an autoclave at that temperature forcrystallization. After full crystallinity was achieved, the majority ofthe hexamethyleneimine was removed from the autoclave by controlleddistillation and the zeolite crystals separated from the remainingliquid by filtration, washed with deionized H₂ O and dried. A portion ofthe zeolite crystals was then combined with Al₂ O₃ to form a mixture of65 parts, by weight, zeolite and 35 parts Al₂ O₃. Water was added tothis mixture to allow the resulting catalyst to be formed intoextrudates. The catalyst was activated by calcining in nitrogen at 540°C. (1000° F.), followed by aqueous ammoninum nitrate exchange andcalcining in air at 540° C. (1000° F.).

The resultant catalyst was charged to a reactor and the reactor waspressurized to 4930 kPa (700 psig) with hydrogen and pre-heated to 450°C. The reactor temperature was reduced to 400° C. and2-methylnaphthalene was fed to the reactor concurrently with H₂. Processconditions were: WHSV=2, H₂ /2-methylnapthalene (molar)=10, and 4930 kPa(700 psig). The reactor was allowed to equilibriate for 10 hours andafter 24 hours, the reaction products were collected and analyzed. Thereactor temperature was subsequently raised to 450° C. and 498° C. andsimilar analyses were made. Table H below summarizes the results of theproduct analyses.

                  TABLE H                                                         ______________________________________                                        Days-on-Stream          1      3      5                                       ______________________________________                                        Temperature, °C. 400    450    498                                     Product Composition, wt. %                                                    Naphthalene             2.00   6.47   13.37                                   2-Methylnaphthalene     78.88  57.57  52.50                                   1-Methylnaphthalene     15.04  26.53  21.21                                   Dimethylnaphthalenes    1.73   6.15   9.55                                    2,6-Dimethylnaphthalene 0.29   0.90   1.56                                    2,7-Dimethylnaphthalene 0.25   0.95   1.39                                    1,6-Dimethylnaphthalene 0.46   1.75   2.89                                    2,3-Dimethylnaphthalene 0.18   0.40   0.66                                    Other Dimethylnaphthalene                                                                             0.55   2.15   3.05                                    Tri- and tetra-         0.28   0.67   0.77                                    methylnaphthalenes                                                            Other Compounds*        2.07   2.61   2.61                                    Conversion of methylnaphthalene (MN), wt. %                                                           6.1    15.9   26.4                                    Product Selectivities, wt. %                                                  DMN (dimethylnaphthalene)                                                                             28.4   38.7   36.1                                    2,6-DMN                 4.8    5.7    5.9                                     2,6- and 2,7-DMN        8.9    11.6   11.2                                    C.sub.13.sup.+          4.6    4.2    2.9                                     DMN/Naphthalene × 100                                                                           86.6   95.0   71.4                                    2,6-DMN/Total DMN × 100                                                                         16.8   14.7   16.4                                    2,6- + 2,7-DMN/Total DMN × 100                                                                  31.0   30.1   31.0                                    MN Isomerization (%)    16.0   31.5   28.8                                    2-MN/1-MN               19.1   46.1   40.4                                    ______________________________________                                         *Includes small amounts of methane, ethylnaphthalenes and other compounds                                                                              

EXAMPLE 16 (COMPARATIVE)

A 65% ZSM-5/35% Al₂ O₃ extrudate was crushed, sized to 24/40 mesh andcharged to a reactor. Properties of this catalyst are set forth in TableI as follows:

                  TABLE I                                                         ______________________________________                                         Catalyst Properties                                                          ______________________________________                                        Surface Area, m.sup.2 /g                                                                          338                                                       Density, g/cc                                                                 Packed             0.566                                                      Particle           0.914                                                      Real               2.629                                                      Pore Volume, cc/g  0.714                                                      Pore Volume, A     85                                                         Ash, wt. % @ 1000° C.                                                                     92.23                                                      Alpha Value        246                                                        ______________________________________                                    

The reactor was pressurized to 4930 kPa (700 psig) with hydrogen andpre-heated to 450° C. The reactor temperature was reduced to 400° C. and2-methylnaphthalene was fed to the reactor concurrently with H₂. Processconditions were as in Example 15. The reactor was allowed toequilibriate for 10 hours and after 5 hours, the reaction products werecollected and analyzed. The ZSM-5 catalyst of this example tended to agemore rapidly than the catalyst of Example 15. Over the course of thenext 48 hours, the reactor temperature was raised to 497° C. and 548° C.Analyses of the products are set forth in Table J as follows:

                  TABLE J                                                         ______________________________________                                        Days-on-Stream    1        2        3                                         ______________________________________                                        Temperature, °C.                                                                         400      497      548                                       Product Composition, wt. %                                                    Naphthalene       7.30     9.24     17.94                                     2-Methylnaphthalene                                                                             61.10    57.06    42.91                                     1-Methylnaphthalene                                                                             25.66    20.27    18.03                                     Dimethylnaphthalenes                                                                            3.27     8.05     10.04                                     2,6-Dimethylnaphthalene                                                                         0.68     1.31     1.74                                      2,7-Dimethylnaphthalene                                                                         0.73     1.44     1.85                                      1,6-Dimethylnaphthalene                                                                         0.89     2.44     3.09                                      2,3-Dimethylnaphthalene                                                                         0.23     1.31     1.71                                      Other Dimethylnaphthalene                                                                       0.74     1.55     1.65                                      Tri- and tetra-   1.32     2.65     3.18                                      methylnaphthalenes                                                            Other Compounds*  1.35     2.73     7.90                                      Conversion of MNs, wt. %                                                                        13.2     22.7     39.1                                      Product Selectivities, wt. %                                                  DMN (dimethylnaphthalene)                                                                       24.7     35.5     25.7                                      2,6-DMN           5.1      5.8      4.5                                       2,6- and 2,7-DMN  10.7     12.1     9.2                                       C.sub.13.sup.+    10.0     11.7     8.1                                       DMN/Naphthalene × 100                                                                     44.8     87.1     56.0                                      2,6-DMN/Total DMN × 100                                                                   20.8     16.3     17.0                                      2,6- + 2,7-DMN/Total DMN                                                                        43.1     34.2     35.8                                      MN Isomerization  29.6     26.2     29.6                                      2-MN/1-MN         42.0     35.5     42.0                                      ______________________________________                                         *Includes small amounts of methane, ethylnaphthalenes and other compounds                                                                              

A comparison of the data in Table H of Example 15 and Table J of thisexample shows that the catalyst of the invention is more selective forthe production of dimethylnaphthalenes and that the difference in DMNselectivities is accounted for in the larger amount of tri- andtetramethylnaphthalenes (C₁₃ +) produced by ZSM-5. From gaschromatographic analysis, it is further apparent that the catalyst ofthe present process is significantly more selective for the productionof dimethylnaphthalenes than ZSM-5, dimethylnaphthalene losses to thetri- and tetramethylnapahthalenes being much lower with the presentcatalyst.

What is claimed is:
 1. A process for the disproportionation ofmethylnaphthalenes which comprises contacting at least onemethylnaphthalene under disproportionation reaction conditions with adisproportionation catalyst to provide a product containing naphthaleneand at least one dimethylnaphthalene isomer, said disproportionationcatalyst comprising a synthetic porous crystalline materialcharacterized by an X-ray diffraction pattern including valuessubstantially as set forth in Table A of the specification.
 2. Theprocess of claim 1 wherein the synthetic porous crystalline material ischaracterized by an X-ray diffraction pattern including valuessubstantially as set forth in Table B of the specification.
 3. Theprocess of claim 1 wherein the synthetic porous crystalline material ischaracterized by an X-ray diffraction pattern including valuessubstantially as set forth in Table C of the specification.
 4. Theprocess of claim 1 wherein the synthetic porous crystalline material ischaracterized by an X-ray diffraction pattern including valuessubstantially as set forth in Table D of the specification.
 5. Theprocess of claim 1 wherein the synthetic porous crystalline material hasa composition comprising the molar relationship

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein n is at least about 10, X is a trivalent element and Y is atetravelent element.
 6. The process of claim 1 wherein the syntheticporous crystalline material possesses equilibrium adsorption capacitiesof greater than about 4.5 wt. % for cyclohexane vapor and greater thanabout 10 wt. % for n-hexane vapor.
 7. The process of claim 5 wherein Xis selected from the group consisting of aluminum, boron, gallium andcombinations thereof and Y is selected from the group consisting ofsilicon, germanium and combinations thereof.
 8. The process of claim 5wherein X comprises aluminum and Y comprises silicon.
 9. The process ofclaim 1 wherein said synthetic porous crystalline material has beentreated to replace original cations, at least in part, with a cation ormixture of cations selected from the group consisting of hydrogen,hydrogen precursors, rare earth metals, and metals of Groups IIA, IIIA,IVA, IB, IIB, IIIB, IVB, VIB and VIII of the Periodic Table.
 10. Theprocess of claim 1 wherein said synthetic porous crystalline materialhas been thermally treated at a temperature up to about 925° C. in thepresence or absence of steam.
 11. The process of claim 9 wherein saidsynthetic porous crystalline material has been thermally treated at atemperature up to about 925° C. in the presence or absence of steam. 12.The process of claim 1 wherein said synthetic porous crystallinematerial is combined with a matrix material.
 13. The process of claim 12wherein said matrix material is selected from the group consisting ofsilica-containing material, alumina-containing material,zirconia-containing material, titania-containing material,magnesia-containing material, beryllia-containing material,thoria-containing material, and combinations thereof.
 14. The process ofclaim 12 wherein the catalyst is provided in the form of extrudate,beads or fluidizable microspheres.
 15. The process of claim 1 whereinthe methylnaphthalene is 2-methylnaphthalene.
 16. The process of claim 1wherein a mixture of methylnaphthalenes is disproportionated with2-methylnaphthalene representing at least about 20 weight percent of thetotal methylnaphthalenes.
 17. The process of claim 1 wherein a mixtureof methylnaphthalenes is disproportionated with 2-methylnaphthalenerepresenting at least about 50 weight percent of the totalmethylnaphthalenes.
 18. The process of claim 1 wherein thedisproportionation conditions include a temperature of from about 300°to about 675° C., a pressure of from about atmospheric to about 2000psig and a weight hourly space velocity (WHSV) of from about 0.1 toabout 500 hr⁻¹.
 19. The process of claim 1 wherein thedisproportionation conditions include a temperature of from about 375°to about 575° C., a pressure of from about 200 to about 1000 psig and aweight hourly space velocity (WHSV) of from about 0.5 to about 100 hr⁻¹.